1. Field of the Invention
This invention relates to a camera lens barrel having a reduced diameter. In particular, this invention is drawn to a camera lens barrel having a lens shift means and a lens shift drive means for moving a lens group of the camera lens barrel in a direction perpendicular to the optical axis of the camera lens barrel.
2. Related Art
In the conventional camera lens barrels where one of the lens groups can be shifted in a direction perpendicular to the optical axis of the lens barrel, the lens drive mechanism is separated into a lens shift mechanism and a lens shift driver. The lens shift driver in the conventional camera lens barrel is attached to the main body of the camera. A shift drive transmission is used to transmit shift drive power from the lens shift driver to the lens shift mechanism, which is displaced from the lens shift driver along the optical axis. This shift drive transmission has an axis of rotation which is parallel to the optical axis. Rotation of the shift drive transmission transmits power from the lens shift driver the lens shift mechanism. Such a conventional camera lens barrel is disclosed in, for example, Japan Published Patent Application 3-110530.
In this conventional camera, the shift drive transmission transmits the shift drive power regardless of the shift state of the shiftable lens group. Thus, in this conventional camera, it has been necessary to place the shift drive transmission radially outside of, or further from, the optical axis than the diaphragm driver and the lens shift mechanism. As a result, the diameter of the camera lens barrel is significantly increased.
In addition, when the camera lens barrel includes a zoom lens, the focusing lens driver, which is used to move the focusing lens group along the optical axis, is located on the outer surface of the focusing lens group. However, the focusing lens group tends to be relatively larger in diameter than the other lens groups of the zoom lens. Thus, when the focusing lens driver is located on the outer perimeter of the focusing lens group, the already enlarged diameter of the camera lens barrel grows even larger. These enlarged camera lens barrels become unwieldy and difficult to use.